Friday, February 25, 2011

With one arm raised and a determined scowl, the figure looks ready to march right off his carved tablet and into the history books. If only we knew who he was - corn god? Tribal chief? Sacred priest?

"It's beautiful and was obviously very important," says University of Wisconsin-Madison archaeologist John Hodgson of the newly discovered stone monument. "But we will probably never know who he was or what the sculpture means in its entirety."

The man is the central figure on a stone monument discovered in 2009 at a site called Ojo de Agua in far southern Mexico in the state of Chiapas along the Pacific coast. Hodgson, a doctoral candidate in anthropology at UW-Madison, describes the new monument in the cover article of the current issue (December 2010) of Mexicon, a leading peer-reviewed journal of Mesoamerican studies. The article, titled "Ojo de Agua Monument 3: A New Olmec-Style Sculpture from Ojo de Agua, Chiapas, Mexico," is co-authored with John E. Clark, of Brigham Young University, and Emiliano Gallaga Murrieta, director of the National Institute of Anthropology and History in Chiapas.

Monument 3 is just the second carved monument found in Ojo de Agua. Monument 1 was discovered accidently when a local farmer hit it with a plow in the 1960s. Monument 3 was a similarly fortuitous finding, uncovered in the process of digging an irrigation ditch. (Monument 2 is a large boulder with a flat surface and no visible carving, which Hodgson found in 2005 and reported in the January/February 2006 issue of Archaeology magazine in an article on Ojo de Agua.)

Hodgson was working in the area and received word of the finding within just a few days of its discovery. He was able to see the monument's impression in the trench wall and study the soil layers where it had been buried, gaining a wealth of information that is usually lost long before any archaeologist lays eyes on a piece.

"Usually sculptures are first seen by archaeologists in private art collections and we normally have no good idea where they came from. The depictions of figures and the motifs change in form through time so you can get an approximate date by comparing styles," he says. "But we were able to date the new monument by where it was found to a narrow 100-year window, which is very rare."

The archaeological context and radiocarbon dating of ceramic sherds associated with the stone monument show that it dates to 1100 to 1000 B.C., making it approximately 3,000 years old. Its age and style correspond to the Early Formative period, when an early culture known as the Olmec dominated the area.

Its purpose and meaning, however, will be harder to ascertain.

"Everything means something in this kind of culture," says pre-eminent archaeologist Michael D. Coe, a professor emeritus of anthropology at Yale University and expert on Mesoamerican civilizations. "It obviously was a public monument — an important one, probably in connection with some really big cheese who lorded it over the area." Coe was not directly involved in the work but is familiar with the newly discovered monument.

"It appears to me to be a depiction of an event or a way to convey other types of information," Hodgson adds. "This dates to a time prior to a developed written language, but like the modern symbol used internationally for the Red Cross, symbols are very efficient at communicating complicated ideas."

The main figure on the tablet is depicted wearing an elaborate headdress, loincloth and ornate accessories, including a pair of large, comb-like ear ornaments, a rope-like necklace and a thick belt with a jaguar-head buckle. A face on the headdress includes features such as sprouting plants that identify it as a corn god. The tablet also includes a smaller secondary figure and a series of asymmetric zigzag designs that the authors suggest could represent lightning, local mountain ranges, or other features of the natural world.

"This is closely connected with agriculture and the cult of the corn god," Coe says, pointing out the zigzags. "Thunderstorms bring the rain."

The monument is a carved flat slab of a relatively soft, local volcanic stone that weighs about 130 pounds. It stands nearly three feet tall, about 14 inches wide, and ranges from four to seven inches thick. The use of local materials shows it was made in or near Ojo de Agua, Hodgson says, but style similarities to pieces found in larger Olmec centers near the Gulf of Mexico and the Valley of Mexico indicate pan-regional influences as well.

"It's cruder in execution than most Olmec monuments from the other side of the isthmus — 'provincial' Olmec," Coe says. But despite lacking some of the intricate artistry, it is still relatively sophisticated, he says. "This adds to our knowledge of the Olmec on the south side of the isthmus."

The depiction of corn is particularly notable. Corn cultivation is generally associated with a settled lifestyle rather than a nomadic existence, indicating that Ojo de Agua was almost certainly a farming community. The grain's storability and nutritional content also would have allowed the population to expand drastically and the civilization to become more complex, Hodgson says, adding that "the early date of the monument supports the idea that there was an early association between corn and religion."

Ojo de Agua lies in the heart of the ancient Aztec province Soconusco, nestled in a bend of the Coatán River. It is the earliest known site in Mesoamerica with formal pyramids built around plazas.

Though it has not been worked very extensively as an archeological site, Ojo de Agua appears to cover about 200 hectares and is the largest site in the area from the time period 1200-1000 B.C. The limited work to date describes civic architecture consistent with a decent-sized planned settlement. The identified platform mounds are laid out in a deliberate alignment that may be relative to magnetic north.

"That's something we see later but to see it this early is pretty surprising," says Hodgson, who has been working at Ojo de Agua since 2003.

The site appears to have been occupied for 150 to 200 years before being abandoned for unknown reasons.

Hodgson expects there are many more clues at Ojo de Agua and hopes to have the opportunity to continue working at the site and perhaps another look at Monument 3.

"We've just scratched the surface there. The things we've found are fantastic," Hodgson says. "These early societies were a lot more complicated than we thought they were."

(Photo: John Hodgson; Drawing: Kisslan Chan and John Clark, New World Archaeological Foundation)

Think you're overloaded with information? Not even close. A study appearing on Feb. 10 in Science Express, an electronic journal that provides select Science articles ahead of print, calculates the world's total technological capacity — how much information humankind is able to store, communicate and compute.

"We live in a world where economies, political freedom and cultural growth increasingly depend on our technological capabilities," said lead author Martin Hilbert of the USC Annenberg School for Communication & Journalism. "This is the first time-series study to quantify humankind's ability to handle information."

So how much information is there in the world? How much has it grown?

Prepare for some big numbers:

* Looking at both digital memory and analog devices, the researchers calculate that humankind is able to store at least 295 exabytes of information. (Yes, that's a number with 20 zeroes in it.)

Put another way, if a single star is a bit of information, that's a galaxy of information for every person in the world. That's 315 times the number of grains of sand in the world. But it's still less than one percent of the information that is stored in all the DNA molecules of a human being.

* 2002 could be considered the beginning of the digital age, the first year worldwide digital storage capacity overtook total analog capacity. As of 2007, almost 94 percent of our memory is in digital form.

* In 2007, humankind successfully sent 1.9 zettabytes of information through broadcast technology such as televisions and GPS. That's equivalent to every person in the world reading 174 newspapers every day.

* On two-way communications technology, such as cell phones, humankind shared 65 exabytes of information through telecommunications in 2007, the equivalent of every person in the world communicating the contents of six newspapers every day.

* In 2007, all the general-purpose computers in the world computed 6.4 x 10^18 instructions per second, in the same general order of magnitude as the number of nerve impulses executed by a single human brain. Doing these instructions by hand would take 2,200 times the period since the Big Bang.

* From 1986 to 2007, the period of time examined in the study, worldwide computing capacity grew 58 percent a year, ten times faster than the United States' GDP.

"These numbers are impressive, but still miniscule compared to the order of magnitude at which nature handles information" Hilbert said. "Compared to nature, we are but humble apprentices. However, while the natural world is mind-boggling in its size, it remains fairly constant. In contrast, the world's technological information processing capacities are growing at exponential rates."

According to Dr Annette Baudisch of the Max Planck Institute for Demographic Research in Rostock, Germany, current methods of comparing patterns of ageing are limited because they confound two different elements of ageing – pace and shape.

"Some organisms live a short time, others live a long time. This is the pace of ageing. Short-lived species have a fast pace of ageing, and long-lived species have a slow pace of ageing. Pace describes how quickly the clock of life ticks away. For humans it ticks slowly, for small songbirds like the robin it ticks very fast," explains Dr Baudisch.

By contrast the shape of ageing describes how much mortality – the risk of dying – changes with age. One way of measuring the shape of ageing is the 'ageing factor'. For example, the common swift has an ageing factor of 2, meaning mortality doubles during its adult life, compared with modern humans, who have an ageing factor that exceeds 2000.

"At the age of 15, only 2 out of 100,000 girls in Sweden die, but one out of every two women aged 110 will die. This large difference in mortality at the beginning and end of adult life means that for humans the shape of ageing is steep, whereas in other species like the common swift it is shallow. And in some species the risk of death can even fall with age, with older individuals having the least risk of dying. This seems to be the case for the desert tortoise, and for alligators or crocodiles."

Using data for 10 different groups of animals from herring gull, European robin, common swift and lake sturgeon to Dall mountain sheep, African buffalo, wild and captive chimpanzees, hunter-gatherers and modern humans (Swedish women), Dr Baudisch classified how each species aged in terms of pace and shape of ageing.

Of the species she analysed, Dr Baudisch found that although modern humans are the longest-lived, they also age most strongly.

Adult life expectancy for Swedish women (that is the remaining life expectancy after reaching maturity) is about 70 years, whereas a robin's adult life lasts just 1.7 years. But over that adult lifespan, ageing is so strong in the human that the ageing factor is 2132, but for the robin only about 2.

"Comparing robins with Swedish women, humans have a slow pace of ageing whereas the robin's is fast, so in terms of length of life the humans are doing best. But if we look at the impact ageing has on death rate the robin wins. Its shape of ageing is fairly flat whereas the humans' is steep, indicating that death rates increase markedly with age," she says.

Dr Baudisch's results have important implications for evolutionary biology and the study of ageing: "We need to compare species to understand how evolution has shaped the biology of ageing in different species, but current methods of comparing patterns of ageing across species are limited because they confound the pace and shape of ageing. Not accounting for this difference can lead to incorrect conclusions about which species age more than others."

"Separating pace from shape of ageing gives a clearer picture of the characteristics of ageing. It could reveal that certain species are very similar to each other in terms of their shape of ageing, species that we would maybe never have grouped together. Ultimately, this should help us identify the determinants of ageing – the characteristics that determine whether death rates goes up or down with age and reveal species that can successfully avoid ageing," she says.

In more everyday terms, her results might make us re-think common expressions, such as "live fast, die young". As dying young in Dr Baudisch's terms corresponds to a small ageing factor and dying old to a large one, "live fast, die young" only applies to some short-lived species.

Robins live fast and die young, but even though Dall mountain sheep only live for around 4.2 years, their ageing factor is 7.

"Not all species with short lives live fast and die young. Robins do, but mountain sheep do things differently. They also live pretty fast but die older. From the data I have, it seems that live fast die young is only one option; you can also live fast and die older, or live slower and die young, or live slow and die old. There might be every combination in nature. That's something we need to find out in the future with better data."